Louie, is the tube attached at one end, or sewn along the side(s) to attach it to the strap? I don't recall seeing a sheath for a measure that was just attached at one end, but I've seen the remnants of something that at one time was attached to the strap. I've only seen those on later, machine-sewn bags that seemed to be a commercial product, suggesting it might (and that is a highly-qualified "might") be a later characteristic.
I've always wondered about the watch chains. I know that in some cases, use of ML continued long past the introduction and popularization of cartridge guns, and many of the old guns were returned to use during the Great Depression and the ammo restrictions of WWII. It seems to me (with little justification) that perhaps the use of watch chains came about after the main period of ML use, when companies like Sears Roebuck and Montgomery Wards made such commodities easily available and at an economical price. Or maybe folks just wanted a means of attachment that wasn't as likely to break as a piece of string or leather . . . .
Sloe Bear, if I want to shoot the smallest possible groups, have the certainty of filling a tag, or be prepared to fight, I don't reach for my flintlock: modern alternatives are far more efficient and reliable. I looking to past practices as a way of seeking understanding about the past.
There are many accounts of people in the west avidly seeking news, and buying the latest fashions they could access; it was a time when far more emphasis was placed on dressing for one's station in life. Accounts exist of expectations that people working at trading posts upriver or in the north would wear European-styled clothes in order to make an impression on the natives and to maintain their standing in the community, and of the same people buying leather clothes and beaded finery when going east because that was what was expected of them.
At the time the photos were taken, Tobin was an army scout and bounty hunter. His famous coat was given to him by the governor of Colorado in 1863 or '64, after he hunted down, killed, and beheaded a couple of murderers. He dressed the way he was expected to look (and part of that was probably an expectation of Native influence as he was a "half-breed"). His half-brother, Charles Autobee, was also a scout--during his years as a scout he dressed in a similar manner, and later as a rancher/saloon keeper, he dressed in then-conventional clothes that fit those roles.
Medina was a "frontiersman" who ran a ferry etc. He dressed to meet the social expectations of how a frontiersman looked. (He also had a bit of a reputation as a "clothes horse.")